It's easy to identify many investment managers with great recent records. But past results, though important, do not suffice when prospective performance is being judged. How the record has been achieved is crucial.
Warren BuffettTake the probability of loss times the amount of possible loss from the probability of gain times the amount of possible gain. That is what we're trying to do. It's imperfect, but that's what it's all about.
Warren Buffett